1997 806TD not starting ECU or Diesel pump?

[thomascrook]

Dear All
New on here yesterday and I'd like to ask for your opinion
I have an 806 that just refuses to start.
Firstly the battery went flat and whilst it was flat I removed the ignition with the intention of swapping it due to wear (key difficult to turn)
It is now all together and battery charged but will not have any of it
immobiliser works as it should, i.e. red light on then insert the key....light goes out
Recovery guy put a booster on the battery and also jump leads to try to start it.....maybe causing some damage?
Auto electrician has given up very quickly due to "no communication" message from his tool
At another mechanic now and he has said fuel is getting to the Diesel pump, but not coming out of it....may be leading to an ECU problem
So, at this point it is in his opinion it is either the ECU or the DIESEL pump that is at fault....or wiring elsewhere??
A real head scratcher
Any help would be gratefully received, I love these cars and never like to see them go to the scrappy
...........Also anybody ever fitted a donor ECU? and if so, what is involved trying to avoid the main dealer obviously.....Cheers!!

[ekjdm14]

Did you swap the transponder "pellet" from your old key into the new one? I think the ECU and transponder are "paired" but little else on this age of car.

I think, although am open to correction, that an ECU swap would be as simple as swapping the ECU and transponder pellet over. The main issue I can see is finding a correct ECU.

What engine precisely is fitted? if it's 2.1 with the EPIC pump then I may be able to help out. You could bring the ECU and key/transponder & we could try them in my 406 (for proving out purposes) if the numbers happen to match. We're in Congleton so not a million miles away. Let me know if you're interested and we'll compare the numbers/arrange something.

EDIT-: again, assuming it's a 2.1/EPIC setup here's CitroJim's guide to overhauling the pump https://www.frenchcarforum.co.uk/forum/ ... =3&t=45980 although as there's no fuel out I'd lean towards either ECU/immobiliser/wiring or stop solenoid failure, and from the above guide it looks like the stop solenoid would be "do-able" without stripping the pump too far, might even be possible in-situ.

[thomascrook]

Hi ekjdm14
Thank you for your reply and the info
My car is the 1.9TD, but thanks for the offer of the try out
I managed to talk to the previous owner and it works out he has had over a period of time (3 times in the past few years) when he had a problem starting it used easy start down the intake and so then fires up
After reading various posts it seems this fools the stop solenoid to opening so I will try this first
Also to get at the stop solenoid on the Lucas which I think mine is will be a tricky operation to say the least
I will keep this post with what happens tomorrow at the mechanics and maybe it can help someone else
Cheers!

[ekjdm14]

Yes, we bought a ZX with the 1.9TD engine a couple of years ago as a non runner and that was the solenoid that had failed (actually the wire had snapped just where it enters the solenoid). It is indeed a pain to get through the armour, IIRC doing it "properly" entails removing the pump but I went quick & dirty opting to slice the plating off carefully with a combination of 4" cutting disc and dremel, just removing enough to get a hold of the solenoid and replace it didn't take long. maybe 20-30min taking it slowly and making sure not to set the thing alight.

Hope you can get it sorted, the actual solenoid can be had for about 6 quid off ebay.

[thomascrook]

That's great thank you!
What in your opinion gives a "no communication" to a diagnostic tool? On another forum it was suggested that no power was getting to the ECU
any ideas?

[Paul-R]

On my daughter's 206 it was two of the pins in the EOBD socket that were misaligned. These were carefully pushed back into shape and then everything worked.

[CitroJim]

Which ECU are you trying to communicate with? If it is the Pump (Injection) ECU then that will not communicate with diagnostics if the immobilier is not disarmed..

It sounds like the immobiliser is not being correctly disarmed after your ignition switch swap. This will make it appear there is a lack of power to the ECU

You should be able to 'fool' the immobiliser into dearming by holding the old key near to the new ignition switch whilst switching on with the new key.

If the immobiliser is not disarming a light should appear on the dash, accompanied by bleeping...

You may just need to re-programme the new key... if you did not transfer the RFID chip 'pellet' as ekjdm previously advised...

Never use EasyStart. It's not good for the engine...

As it's a 1.9TD I'll assume it's got a Bosch AS3 pump and if push comes to shove the immobiliser can be removed and the stop solenoid operated direct from a switched ignition supply...

It's not an easy job as the pump needs to be de-armoured first... This is a last resort only...

[thomascrook]

Well an update on my post!!

Took the previous owner to the garage who is a friend as he was adamant that he could get it going

Opened the bonnet connected a few things up and sprayed some easy start up the intake.....3 times!

With a battery booster the car fired up...... after the third attempt. The outcome we believe is that the stop solenoid periodically sticks shut and the easy start fools it by telling it it's running and so opens??

I know easy start is not good for the engine but what to do?

The no communication was with the engine ECU I believe, but it is not the problem

To sort the problem long term it seems I would have to remove the pump and change the solenoid which is a major job, timing belt etc.

I'll let you know what happens next and hopefully all will be well for a bit?

Hope this helps if anyone has a similar problem. I'm not mechanic, but learned a few things on here

Many thanks for your time and input

[CitroJim]

With a battery booster the car fired up...... after the third attempt. The outcome we believe is that the stop solenoid periodically sticks shut and the easy start fools it by telling it it's running and so opens??

No, that can't happen... There is no such mechanism...

The fact the engine starts with a whiff of easystart suggests there is something fundamentally wrong...

In the case of a 1.9TD there are two major suspects in this cold weather... Glowplugs or their operation and potentially tight valve clearances...

Effective pre-heating is essential to allow a 1.9TD to start and if the glowplugs are below par or their controller is not working correctly then it'll not start - except without help from easystart or similar... IDI engines like the 1.9TD ALWAYS need pre-heating.

Check the glowplugs are getting a full 12v for at least 20s on turning on the ignition and if you have any doubt about when they were last swapped then replace them.

The XUD engines have an odd quirk whereby the valve clearances are tightest when the engine is stone cold. On days like today when the temperature is below freezing this can cause a few valves to be held slightly open if the clearances are tight. This will again cause the engine not to start.

It only takes a tiny bit of heat for the clearances to open sufficiently to restore normal operation. A dead giveaway this is the problem is the emission of white smoke from the exhaust during cranking.

If you keep using easystart you will cause serious damage to the engine. It is an explosive and it causes the same damage as severe detonation (pinking) does in a petrol engine.

[thomascrook]

Thank you for your replies...

Update to previous is that the car is back to where I started....or not

So I have the car back and the mechanic cannot get it going again and so recovered back to my house where I am left with a decision what to do with it

We did get it going as I mentioned, and turned it off and it started straight away. However 15 mins later the mechanic tried to move it and it wouldn't start again from that point, he tried everything

He tells me there is no fuel getting past the pump, i.e. it feeds to the pump but not from it

We spoke about changing the pump, but I can see he is reluctant as if that's not the fault we would have spent more cash than I paid for it

I have limited knowledge of the mechanical side of the these cars, although I was a panel beater in another life so I'm tempted to tackle trying to get to the stop solenoid as this seems the first and cheapest fix

As usual, any advise would be very welcome, I don't want to scrap this car and I have never experienced a situation where a mechanic has been stumped

I mentioned before that the diagnostic tool on two different occasions with different mechanics will not communicate with the ECU...message "no communication"

Cheers for now

Tom

[CitroJim]

This is a difficult one Tom... Swapping the pump alone will not help as it is coded to the immobiliser and ECU...

It is possible to de-armour the pump and operate the stop solenoid direct from an ignition-switched supply but you still need to be able to have the ECU in full operation or the pump will not work correctly. It will failsafe to a fully retarded timing condition and the engine will barely run...

Before proceeding any further you need ton get some proper diagnostics carried out by an engineer who fully understands the injection and immobiliser system in use on the car to try and determine exactly what the problem is...

[thomascrook]

Hi Citrojim and thanks for your reply

With all the advise and given the history of the car, it would indicate the stop solenoid is the most likely culprit. To get at it and cut through the armour it is a mission but I'm going to give it a go...

The replacement part is cheap and I have the time at the mo

I'll keep you posted and I hope to get to the bottom of it soon

Cheers for now and any other info again, gladly received

Tom

[CitroJim]

Excellent Tom Do go careful de-armouring the pump. Remove it first... I have seen one attempt to do it in-situ that ended in disaster. A lump of armour chipped off and ended up in the inlet tract. Turbo and cylinder head wrecked beyond repair...

Looking forward to news...

[thomascrook]

Yes, was thinking of doing it in situ to avoid replacing the timing belt as I've never got involved this deep into mechanicals

If I do ill be back in here with how to do it hahaha

Thanks Citrojim

[spider]

I did mine in situ however it took me quite a long time as I was so so careful with it I sliced into the top a couple of times to knock the pin out. I then already had some spare bolts to replace the pump head ones (leave a minimum of two diagonally opposite ones present!) as the standard bolts were a tad too long, due to having the armour there too. I'd collected these from the scrapyard from other Bosch pumps at the time so I had a 'collection' of suitable bolts.

You may or may not find your stop solenoid does not have a proper plug on it, mine relied on the armour to be held in place but it was the weird TUD5B unit and the solenoid did not have threads in it. So I ended up with a new solenoid and a neat home made (heatshrunk) lead for it. Out of the 4 wires running to the plug one was ignition live to feed the module its power so it was all good. Incidentally the actual electronic pump 'timing' control worked when using an uncoded key, which shows that the immob is not completely reliant on the ECU as such.